% -------------------------------------------------------------------------
% state parameters
%
% auxdata = statement_
%
% Input argumuents:
% -------------------------------------------------------------------------
% None
%
% Output argumuents:
% -------------------------------------------------------------------------
% auxdata        [structure]           parameters              [ - ]
%
% External functions called:
% -------------------------------------------------------------------------
% None
%
% Copyright(C) 2015/06/22 by Chen Zhang, 
% School of Astronautics, Beihang University
% chenzhang.buaa@gmail.com
% -------------------------------------------------------------------------
function auxdata = statement_
mu = 398600.4329; % Earth gravitational constant (km^3/s^2) 
Isp = 3500; % Specific impulse (s) 
g0 = 9.80665; % Gravitational acceleration (m/s^2)
Tmax = 50; % Maximum thrust force (N, kg*m/s^2)
m0 = 5500; % Initial mass (kg)
tol = 1e-10; % Integration tolerance
% -------------------------------------------------------------------------
LU = 6378.14; % Earth radius, Distance unit(km)
TU = sqrt(LU^3 / mu); % Time unit (s)
VU = LU / TU; % Velocity unit (km/s)
MU = m0; % Mass unit (kg)
% -------------------------------------------------------------------------
auxdata.LU = LU;
auxdata.TU = TU;
auxdata.VU = VU;
auxdata.MU = MU;
% -------------------------------------------------------------------------
% Scaling
mu = mu * TU^2 / LU^3; % dimentionless gravitational constant (dim.less)
Tmax = Tmax * 0.001 * TU^2 / (MU * LU); % Maximum thrust force (dim.less)
Isp = Isp / TU; % Specific impulse (dim.less)
g0 = g0 * 0.001 * TU^2 / LU; % Gravititational acceleration (dim.less)
c = Isp * g0; % Exhaust velocity (dim.less)
% -------------------------------------------------------------------------
auxdata.mu = mu;
auxdata.Tmax = Tmax;
auxdata.c = c;
auxdata.tol = tol;
end
% -------------------------------------------------------------------------